The present invention relates in general to an end surface capillary structure of a heat pipe, and more particularly, to a heat pipe that includes an end surface in contact with the heat source and a wick structure including a plurality of grooves and a powder-sintered attachment.
Having the characteristics of high thermal conductivity, fast thermal conduction, light weight, non-movable components and simple structure, heat pipes are able to deliver large amount of heat without consuming electricity, and are therefore commonly used in the market.
FIG. 1 illustrates a conventional heat pipe 1a that includes a pipe member 10a and a powder-sintered wick structure ha attached to an internal sidewall of the pipe member 10a. The wick structure 11a provides capillary force to transport working fluid filled in the pipe member 1a. However, the fabrication of the wick structure 11a requires an axial bar 12a inserted into the heat pipe 1a for supporting the wick structure ha during powder sintering process to avoid powder collapse. This type of wick structure has the following drawbacks.
1. When the axial bar 2a is inserted into the pipe member 10a of the heat pipe 1a, it is difficult to dispose the axial bar 1a along the axis of the pipe member 10a. Instead the axial bar 1a is easily deviated from the axis to cause non-uniform wick structure 11a, such that the fluid transportation is non-uniform to cause poor thermal conduction.
2. After powder sintering process, the powders for forming the wick structure ha are easily attached to the axial bar 12a to cause problem for removing the axial bar 12a from the pipe member 12a. Therefore, the quality of such heat pipe depends on proficiency of the operator, and it cannot be fabricated by mass production.
3. As it is difficult to remove the axial bar 12a, external force is required for the removal. However, because an annealing process is performed on the wick structure 11a and the pipe member 10a before removing the axial bar 12a, the heat pipe 1a is extremely soft. Therefore, during the removal of the axial bar 12a, the pipe member 10a is easily deformed and the wick structure 11a is easily damaged. Such that the structure precision of the heat pipe 1a will be greatly affected.
Therefore, there exist inconvenience and drawbacks for practically application of the above-mentioned conventional heat pipe. There is thus a substantial need to provide an improved end surface capillary structure of a heat pipe that resolves the above drawbacks and can be used more conveniently and practically.